Mechanical engineering assistant professor Yangying Zhu has received a Young Investigator Award from the Office of Naval Research. 

UC Santa Barbara mechanical engineering assistant professor Yangying Zhu has received a prestigious Young Investigator Award from the Office of Naval Research (ONR). She was one of twenty-four awardees from twenty academic institutions in 2024 recognized by the Young Investigator Program (YIP), which supports innovative research that benefits science and technology for the Department of Navy. Prior academic accomplishments and potential for scientific breakthroughs were key elements in the evaluation of the more than two-hundred applicants. Awardees will receive $750,000 over three years in support of their proposed research projects. Zhu says that the award will fund two graduate students in her research group.

“I am humbled and grateful for this research opportunity to investigate phase-change heat transfer from nanoengineered structures,” said Zhu, who previously received an Early CAREER Award from the National Science Foundation, the Pi Tau Sigma Gold Medal from the American Society of Mechanical Engineers, and an Early Career Award from the National Aeronautics and Space Administration (NASA).

“In order for ONR to support the Sailors and Marines we have the privilege of serving with innovation and scientific and technological excellence, we must identify and attract the brightest scientists and engineers from around the nation,” said Chief of Naval Research Rear Admiral Kurt Rothenhaus. “The Young Investigator Program is critical to that goal, and I am honored to announce the recipients for 2024.”

Rapid advancement in the performance and miniaturization of electronics and high-power devices, such as microchips and data centers, has resulted in huge heat flux values that need to be dissipated effectively. Flow boiling in microchannels is one of the most promising cooling methods for these and similar devices due to their capability of achieving very high heat transfer rates with small variations in the surface temperature. However, several fundamental issues are still not understood, and this prevents a rapid transition from research in labs to commercial applications. Flow boiling refers to the heat transfer mechanism that occurs when a fluid circulates over a heated surface due to external forces, such as a pump, or due to the natural buoyancy effect. Zhu’s proposed project, “Suppressing Flow Boiling Instabilities Using Surface Structures,” seeks to fill in some of those knowledge gaps by investigating flow boiling in microchannels, which are conduits on the order of a few micrometers or millimeters that can be used to enhance heat transfer and control fluids. 

“Flow boiling has the potential to dissipate high heat fluxes from miniaturized devices due to the high-latent heat associated with the liquid-vapor phase change,” she explained. “However, flow boiling suffers from a long-standing instability issue, which causes large temperature oscillations in a system. These variations cause significant mechanical stress that causes electronics to fail.”

Zhu’s research group previously demonstrated that surface structures can enhance boiling heat transfer by helping to supply fluid to the evaporating interface. As part of her ONR program, Zhu plans to use nanoengineered structures to suppress flow instability and gain insight into the role that these structures play in a complex multi-phase thermofluidic system. 

“Through this research, we hope to better understand how nanostructures influence flow boiling instability, which can lead to improved cooling strategies for advanced applications for the Navy,” she said. 

The knowledge gained from this project could potentially be useful in other applications, such as solar thermal desalination, thermal management of data centers, and robotics actuated by liquid-vapor phase change.

Caption: Mechanical engineering PhD student Harsh Shah fine-tunes a device used as part of a research project proposed by his advisor, assistant professor Yangying Zhu, which was supported by the Office of Naval Research.